1. Field of the Invention
The present invention relates to trailers and carriages for transporting and supporting cargo. In particular, the present invention relates to a trailer especially suited for carrying and loading cargo onto ocean-going ships having side or stern ramps.
2. Discussion of Background
Shipping and the ability to transport cargo in vast quantities has made oceanborne shipping the dominant method for the transportation of cargo. Ships that carry manufactured goods, rather than large quantities of bulk goods (wheat, grain, etc.), have numerous levels or decks throughout the ship. These decks are restricted in their height, which maximizes the number of decks per ship. However, by restricting the vertical dimension of these decks, the ability to load and unload cargo into these restricted areas is limited. Consequently, the cargo carrying devices and vehicles that transport the cargo onto and off of the ships must be of the size that will maximize the amount of cargo the ship is able to transport.
These ships that have numerous cargo decks are also known as roll-on, roll-off ships or "Ro-Ro" ships. "Ro-Ro" ships generally have either a side or stern ramp that can be adjusted for tidal variations. These ramps may have very small or relatively very large inclines with respect to the dock or other port facilities.
Often, cargo loads and unloads under its own power, for example, cars, trucks, and construction equipment. However, there is an abundance of cargo that is carried by carriage or pallet systems that must be loaded by trailers or forklifts. Some of the cargo obviously can be too big for a forklift to carry or maneuver within the restricted confines of the ship, and thus must be transported by trailer.
The forklifts or trailers must carry the cargo onto the ship, up the ramp, and then around the decks of the ship to its stowing space. To reach different decks on the ship the trailer and forklifts must also ascend other numerous ramps. Trailers are typically built of a rigid material, so that as the trailer encounters a ramp or other angular change, the back end of the trailer "bottoms out." When a trailer "bottoms out," the back end will scrape the ground or lower surface, thus redistributing the weight of the trailer. This redistributing of the weight may be borne by the towing vehicle, the back end of the trailer, or one of multiple axles on the trailer. Consequently, this action can be very damaging to the trailer, the ramps, and possibly the cargo.
Therefore, there is a need for a trailer that is suitable for loading and unloading cargo onto a ship having a stern or side ramp, which is maneuverable within the vertical and width restrictions of the ship, when loading and unloading this cargo. Furthermore, there is a need for a trailer that can adjust to ramps and inclines, so that the trailer does not "bottom out."